1. Field of the Invention
The present invention relates to a stereo image display technique, by which a 3D image display may produce a stereoscopic image which takes viewpoint into account. By taking viewpoint into account a stereoscopic image may be created which appears to remain at approximately the same location in space as viewpoint changes.
2. Description of Related Art
Methods of implementing a 3D stereoscopic image are described as follows:
First of all, as mentioned in the following description, in order to implement a 3D stereoscopic image, a first image for a left eye and a second image for a right eye need to arrive at both eyes in a manner of being discriminated from each other. For this, various methods are explained as follows. These images shall be referred to as first or left image and second or right image.
Prior art displays which may be viewed as 3D images generally fall into four methods for display of 3D imagery.
The first method employs polarized light images where the planes for left and right images are rotated by approximately 90 degrees. These polarized left and right images pass through polarized spectacles so that the corresponding image reaches the left and right eye. A viewer who tilted their head would degrade the 3D stereoscopic image.
Another similar method employs liquid crystal shutter spectacles which open and close left and right shutters so as to allow the corresponding image to reach the correct eye. Prior art employing liquid crystal shutters do not account for a change in viewing location from one viewer to the next. Therefore a 3D image would appear to be at different locations in space when viewed from differing viewpoints. Thus if one viewer pointed at a 3D stereoscopic object, a viewer at a second viewing location would have difficulty determining what is being pointed at.
A third method employs a lenticular screen provided between a display and both eyes. In particular, a propagating direction of light is refracted via lens on the lenticular screen, whereby different images arrive at both eyes, respectively.
A fourth method requires no spectacles and utilizes parallax barriers so that only the proper image is seen by each eye. This technology shall be referred to as auto stereoscopic.
Prior art applying this method required that the viewer remain in an optimal location for 3D viewing. Other spectators may not be able to see 3D imagery clearly. When it does account for tilting of the head or differing viewpoints it is limited to only one viewer. It is not possible for a second viewer to obtain a 3D image as well unless the second viewpoint is closely aligned with the first viewpoint. This limits prior 3D auto stereoscopic to smaller devices of the handheld variety. This technology is also unable to provide for a second viewer to determine which 3D stereoscopic object is being pointed at by a first viewer.
In one embodiment of the present invention parallax barriers at different locations of the display may have different pitch angles in relation to the display surface at the same time. The parallax barriers shall also be referred to as electronically configurable light guiding louvers, or louvers.
By varying the pitch angle of the louvers in relation to viewpoint for multiple locations of the display, a larger display may be viewed auto stereoscopically. Thus for a viewpoint centered in front of the display louvers on opposite sides of the display would guide the light from the display at angles of slightly differing directions. In this way light from each location of the display is guided towards the intended viewpoint.
In addition another embodiment of the present invention may apply these electronically configurable light guiding louvers in more than one axis concurrently. Thus when one viewer tilts his head the light passing through the louvers is guided to the intended viewing location and is blocked or shielded from other viewing locations.
In addition, prior art employing parallax barriers does not account for a change in viewing location from one viewer to the next. Therefore a 3D image would appear to be at different locations in space when viewed from differing viewpoints. Thus if one viewer pointed at a 3D stereoscopic object, a viewer at a second viewing location would have difficulty determining what is being pointed at. Thus the prior art is limited in interaction with the viewer(s).